X r rod-packing



B. C. McCLURE.

ROD PACKING.

APPLICATION FILED MAY I3. 1919.

1,325,950. Patented Dec. 23, 1919. A

- on an enlarged scale. 1 Throughout the drawings finances.

t nn STATES PATENT FFoE.

, nnmnmn CARL momma, or soAnsnaLE, new YORK.

To all whom it may concern: I

Be it known that L'BnnaAMrN' C. MCCLURE, a citizen of the United States of America, residing at Scarsdale, county of Westchester, State of New-York, have invented certain newand useful Improvements in Rod-Flackings, of which the following is a'specification.

My invention 'relates to piston rod packing such as is used in'steam engines, pumps, air compressors and the like and 1s designed to improve the quality and cheapen the process of manufacture thereof. )ne of the best embodiments of my invention at present known to me is illustrated in the accompanying sheet of drawing in.,which Figure 1 is a cross section ofa stuffing box with my invention applied therein, parts being broken away, and

f Fig 2 is a cross section of the packmg like reference characters indicate like parts. 1, is the cyl inder head through which the piston rod 4:, reciprocates, 2, is the gland of the stufiing box formed on the cylinder head, which gland is forced down on the packing 5, by bolts 3, in the usual way.

The packing itself is composed of the outer wrapping 6, and a core block 8. The outer wrapping is composed of any suitable fabric,

such as asbestos cloth, the layers of which are preferably held together by a layer 7,

of any suitable cement, such as rubber cement, which will retain its adhesive quality under heat and moisture. The core block 8,is formed of layers of any absorbent fabric. Asbestos cloth may also serve for mak ing the core block, though other fabric may be substituted. Astrip. of rubber 9, may also be inserted as shown to. give greater resiliency to the packing.

The packing is placed in the stuiiing box in the position shown .in Fig. .1, with the layers of the core parallel to the axis of the piston rod'so that the pressure of the gland 2, will tend to buckle the layers apart and spread the packing radially of the piston rod and stufling box, completely filling the 'same and continually maintaining a tight joint with the piston rod to prevent leakage of the fluid under pressure in the cylinder.

To secure this result 1n the highest degree the layers of the core block 8,. should not be permanently stuck together, but must be flicting conditions are rolls.

"Specification of Letters Patent. P t t 23, 1919, Application filed May 13, 1919. Seriallil'o. 296,788. I

free to separate when in position for use. On the other hand these layers must be held temporarily together by some inexpensive method during the process of manufacture,

plied and secured in osition. These conoth satisfied accordmg to my present invention by saturating the sheet 'or sheets of fabric from which the core block is to be formed with some llquid such as a solution of starch which will stifi en it when dried, folding the sheet or sheets while still damp and pliable, and finally drying them after folding, as by running the core block through calendering The core block will then hold its shape while the wrapping 6, is applied and secured in position.

When put into use, however, the heat of the stufling boX, if free from moisture, will render the starch so brittle that it will crack,

or powder under the pressure of the gland and free the layers of the core from interadhesion. If, on the other hand,steam or Water penetrates the Wrapping 6, and cementing septum 7, the starch will be softened thereby and thus caused to lose its adhesive power on the core layers. In either case the layers of the core block are, after being put into use, soon freed from interadhesion so that they are free to separate and buckle radially of the stuffing box, and so'hug the piston rod tightly, which is the end sought with all rod packing. This mode of operation is the eXact opposite of that of a folded coreblock the layers of which are stuck together with rubber cement which hardens and toughens under heat and age, or held together by other permanent unyielding fastening means, such as have heretofore generally been used.

The broad principle of the present invention is the use of a means for temporarily holding the layers of the core block in position during manufacture, which shall disintegrate or otherwise lose its holding power under the conditions existing when the pack ing is in use.

The particular method of securing the result herein contemplated is the treatment of the core of the fabric with some solution which will stiffen it when dried, but which will become brittle and lose its adhesive power under high heat and pressure, when dry, and also soften and lose its adhesive power under action of moisture.

that is until the wrapping 6, has been ap Having described my invention, I claim: 1.. A packing having a core formed of fabric in parallel layers treated so, that said layers Will temporarily hold their relative positions under the conditions of manufacture, but are capable of being freed from inter-adhesion under the conditions of use.

2. A piston rod packing having a core of fabric arranged in layers parallel to the axis of the piston and set with a starch-like ma terial which will be reduced to powder by dry heat, then easily fractured under pressure and also freed from adhesive qualities by moisture. v

3. The method of forming a core block for rod'packing which comprises saturating absorbent fabric with a starch-like fluid which stiifens on dryingout, but is reduced to powderby extreme heat and is softened by m0istare, shapingsaid material While damp and pliable to formthe block, and then drying it in position. V

4. The method of forming a rod packing which comprises saturating an absorbent fabric with a starch solution, foldingv it to form acore block While damp and pliable, drying it in folded position and'wrapping with a cemented covering of suitable fabric.

B NJAMIN CARL lVIoGLURE. 

